6.10-stable review patch. If anyone has any objections, please let me know.
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From: Nicolas Dichtel nicolas.dichtel@6wind.com
commit 252442f2ae317d109ef0b4b39ce0608c09563042 upstream.
By default, an address assigned to the output interface is selected when the source address is not specified. This is problematic when a route, configured in a vrf, uses an interface from another vrf (aka route leak). The original vrf does not own the selected source address.
Let's add a check against the output interface and call the appropriate function to select the source address.
CC: stable@vger.kernel.org Fixes: 0d240e7811c4 ("net: vrf: Implement get_saddr for IPv6") Signed-off-by: Nicolas Dichtel nicolas.dichtel@6wind.com Link: https://patch.msgid.link/20240710081521.3809742-3-nicolas.dichtel@6wind.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/ip6_route.h | 20 ++++++++++++++------ net/ipv6/ip6_output.c | 1 + net/ipv6/route.c | 2 +- 3 files changed, 16 insertions(+), 7 deletions(-)
--- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -127,18 +127,26 @@ void rt6_age_exceptions(struct fib6_info
static inline int ip6_route_get_saddr(struct net *net, struct fib6_info *f6i, const struct in6_addr *daddr, - unsigned int prefs, + unsigned int prefs, int l3mdev_index, struct in6_addr *saddr) { + struct net_device *l3mdev; + struct net_device *dev; + bool same_vrf; int err = 0;
- if (f6i && f6i->fib6_prefsrc.plen) { + rcu_read_lock(); + + l3mdev = dev_get_by_index_rcu(net, l3mdev_index); + if (!f6i || !f6i->fib6_prefsrc.plen || l3mdev) + dev = f6i ? fib6_info_nh_dev(f6i) : NULL; + same_vrf = !l3mdev || l3mdev_master_dev_rcu(dev) == l3mdev; + if (f6i && f6i->fib6_prefsrc.plen && same_vrf) *saddr = f6i->fib6_prefsrc.addr; - } else { - struct net_device *dev = f6i ? fib6_info_nh_dev(f6i) : NULL; + else + err = ipv6_dev_get_saddr(net, same_vrf ? dev : l3mdev, daddr, prefs, saddr);
- err = ipv6_dev_get_saddr(net, dev, daddr, prefs, saddr); - } + rcu_read_unlock();
return err; } --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1124,6 +1124,7 @@ static int ip6_dst_lookup_tail(struct ne from = rt ? rcu_dereference(rt->from) : NULL; err = ip6_route_get_saddr(net, from, &fl6->daddr, sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0, + fl6->flowi6_l3mdev, &fl6->saddr); rcu_read_unlock();
--- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5689,7 +5689,7 @@ static int rt6_fill_node(struct net *net goto nla_put_failure; } else if (dest) { struct in6_addr saddr_buf; - if (ip6_route_get_saddr(net, rt, dest, 0, &saddr_buf) == 0 && + if (ip6_route_get_saddr(net, rt, dest, 0, 0, &saddr_buf) == 0 && nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf)) goto nla_put_failure; }